Among conventional vehicle control systems for hybrid vehicles that include an internal combustion engine and a motor (hereinafter, a driving motor) that are both used for driving wheels, there is known a vehicle control system that is capable of, even when a communication network fails, continuing necessary communication by way of a simple configuration and processing and allowing the driving motor to continuously perform wheel driving, the vehicle control system including: multiple electronic control units (ECUs) including a motor control ECU to control the driving motor and a management ECU to control devices other than the driving motor; and two independent networks, i.e., first and second communication networks each built with an independent Controller Area Network (CAN) bus (see, for example, Japanese Unexamined Patent Application Publication No. 2014-118072).
In this vehicle control system, the transmission rate of the second communication network is lower than the transmission rate of the first communication network, and the ECUs transmit and receive travel data essential for travel control and data for improving travel comfortability (hereinafter, comfortability improvement data) via the first communication network, and the ECUs transmit and receive the aforementioned travel data via the second communication network. Then, when both the first and second communication networks are functioning normally, the motor control ECU receives both the travel data and the comfortability improvement data and performs comfortability-oriented travel control. If the first communication network fails, the motor control ECU receives only the travel data via the second communication network and performs only the functions essential for traveling while sacrificing travel comfortability.
Thus, if the first communication network fails, this vehicle control system can cope with the communication network failure simply by changing only reception processing of the ECUs (i.e., changing to receiving and using only the travel data received from the second communication network) without changing transmission processing.